When mice on a fatty diet drank sucralose instead of fructose, they became more sensitive to insulin and gained less weight—but they didn’t do any better than mice that just drank water.

Even though tasting artificial sweetener makes some people’s bodies release insulin, it doesn’t make them feel hungrier or change their blood sugar right after—so the insulin spike doesn’t seem to do anything noticeable yet.

Eating a lot of sucralose (an artificial sweetener) over time might make your body less responsive to insulin and change the good bacteria in your gut, which could make it harder for your body to manage blood sugar.

When overweight people taste a solid sweet made with artificial sweetener (like sucralose), their bodies sometimes release insulin right away—even though there are no calories—just like when they taste real sugar.